JP2008072098A - Semiconductor image sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify an operational expression for a color signal of a semiconductor image sensor and to improve the sensitivity. <P>SOLUTION: The semiconductor image sensor includes a plurality of pixels each having a photoelectric converting means and a MOS transistor selectively reading out signal charges of the photoelectric converting means. First pixels 73A and second pixels 73B are arrayed horizontally by turns and vertically by turns, each first pixel 73A having a complementary color filter arranged and each second pixel 73B having a primary color filter arranged. Each first pixel 73A comprises a plurality of photoelectric conversion regions which differ in depth, an intersection region of a straight line connecting obliquely successive first pixels and a straight line connecting obliquely successive second pixels is defined as a virtual pixel 73i, and three primary color signals for the virtual pixel 73i are generated from signal charges accumulated in at least two first pixels 73A and two second pixels 73B which are adjacent to each other in an oblique direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor image sensor used for a video camera, a digital still camera, or the like.

  The semiconductor image sensor is a semiconductor device that includes a plurality of pixels including photoelectric conversion means and a MOS transistor, and selects and reads signals from the pixels by the MOS transistor. In recent years, this semiconductor image sensor, in particular, a so-called CMOS image sensor manufactured by a CMOS (complementary MOS) process has a low voltage, low power consumption, multiple functions, and an SOC (system-on) that can be integrated into one chip with peripheral circuits. Chip). Therefore, it is attracting attention and used as an imaging device for a camera for a mobile phone, a digital still camera, a digital video camera, or the like.

  FIG. 26 shows an example of the configuration (equivalent circuit) of the semiconductor image sensor. In the CMOS image sensor 1, a plurality of pixels 3 each including a photodiode 2 for performing photoelectric conversion and a plurality of MOS transistors for selectively reading out the photodiode 2 are two-dimensionally arranged on the same semiconductor substrate. An imaging element forming region 4 is provided. Furthermore, peripheral circuits 5 and 6 for selecting pixels and outputting signals are provided around the image sensor formation region 4 on the same semiconductor substrate. The region including the circuit 5 and the output circuit 6 for pixel selection is called a peripheral circuit formation region. In the imaging element formation region 4, each pixel 3 is composed of one photodiode 2 and a plurality of MOS transistors, in this example, three MOS transistors including a transfer transistor 8, a reset transistor 9, and an amplification transistor 10. Yes. In the peripheral circuit formation region, a pixel selection circuit (vertical scanning circuit) 5 and an output circuit (horizontal scanning / output circuit) 6 are configured using CMOS transistors.

  In FIG. 26, the photodiode 2 is connected to the source of the transfer transistor 8. A transfer wiring 11 is connected to the gate of the transfer transistor 8. The drain of the transfer transistor 8 is connected to the source of the reset transistor 9, and a so-called floating diffusion FD between the drain of the transfer transistor 8 and the source of the reset transistor 9 is connected to the gate of the amplification transistor 10. The gate of the reset transistor 9 is connected to the reset wiring 12. Further, the drain of the reset transistor 9 and the drain of the amplification transistor 10 are connected to a power supply wiring 13 for supplying power. The source of the amplification transistor 10 is connected to the vertical signal line 14.

In the CMOS image sensor 1, photoelectric conversion is performed in the photodiode 2. Photoelectrons (signal charges) of the photodiode are selected by the transfer transistor 8 and transferred to the floating diffusion FD through the transfer transistor 8. Since the floating diffusion FD is connected to the amplification transistor 10, a signal corresponding to the potential of the floating diffusion FD is output to the vertical signal line 14 through the amplification transistor 10.
The reset transistor 9 resets the signal charge of the floating diffusion FD by discarding the signal charge of the floating diffusion FD to the power supply wiring 13. The horizontal wirings 11, 12, and 13 are common to the pixels 3 in the same row, and are controlled by a circuit 5 for pixel selection.

  Conventionally, a general color solid-state imaging device is provided with a color filter for each pixel and detects an optical signal having a specific wavelength transmitted through the color filter. Therefore, the light reaching the semiconductor portion that performs photoelectric conversion becomes a part of the incident light, and the signal output is reduced as compared with the case where no color filter is mounted.

  Further, in Patent Document 1, as “color separation in an active pixel imaging array using a triple well structure”, signals of three primary colors (red, green, and blue) are detected without using a color filter. A photodetector using a pn photodiode having a three-layer structure has been proposed. According to this proposal, the terminals of each photodiode are formed at the semiconductor interface, and each terminal is connected to the gate of a MOS transistor that functions as an amplifier, so that the signal of each photodiode is amplified and read out.

  FIG. 25 shows the configuration of the optical sensor in Patent Document 1. This optical sensor 131 includes an n-type semiconductor layer (well region) 133 on a p-type semiconductor substrate 132, a p-type semiconductor layer (well region) 134 thereon, and an n-type semiconductor layer (well region) 135 on the semiconductor interface thereon. And a combination of the p-type semiconductor substrate 132 and the n-type semiconductor layer 133, a combination of the n-type semiconductor layer 133 and the p-type semiconductor layer 134, and a combination of the p-type semiconductor layer 134 and the n-type semiconductor layer 135. Three photodiodes are formed, a red photodiode, a green photodiode, and a blue photodiode. The red, green, and blue photodiodes are connected to current meters 141, 142, and 143 for detecting signal charges accumulated in the photodiodes.

Both the CMOS image sensor and the optical sensor described above utilize the fact that the light absorption coefficient of a semiconductor depends on the wavelength of light with respect to color separation.
In the optical sensor 131 of Patent Document 1, in the same semiconductor substrate 132, the short wavelength, that is, the blue light photoelectric conversion portion (photodiode) is the uppermost layer, and the long wavelength, that is, the red light photoelectric conversion portion (photodiode) is the lowermost layer. In addition, color separation is performed by providing a photoelectric conversion portion (photodiode) of the intermediate wavelength, that is, green light in the intermediate layer. According to this, incident light can be used without waste, and the signal output can be increased as compared with a general color filter system. Also, two-dimensionally, since three types of color signals can be extracted from the same location, the color resolution can be increased as compared with a color filter system that extracts one type of color signal from one pixel. However, since the electrodes of each photodiode are shared with the electrodes of photodiodes adjacent in the depth direction, the signal voltage of one photodiode is affected by the signal voltage of another photodiode adjacent in the depth direction. As a result, it is difficult to take out the signal of each photodiode independently. Further, when resetting each photodiode, there is a problem that S / N cannot be obtained because kTC noise due to the capacitance of the photodiode is applied.

  On the other hand, in Patent Document 2, light reception in which magenta filters are stacked using a color filter in which a magenta (Mg) filter as a complementary color filter and a green (G) filter as a primary color filter are alternately arranged in a vertical direction and a horizontal direction is used. Red (R) and blue (B) color signals are detected by the first and second semiconductor layers separated in the depth direction of the part, and a green (G) color signal is detected by the light receiving part in which the green filters are stacked. A MOS-type color solid-state imaging device configured as described above has also been proposed. According to this, faithful color reproducibility can be achieved, and high image quality can also be achieved.

JP-T-2002-513145 JP 2004-281773 A

  By the way, in the MOS type semiconductor image sensor as described above, it is desired to improve sensitivity while suppressing color mixing and noise and having high color separation. Further, in order to increase the speed and simplification of signal processing, further simplification of an arithmetic expression for detecting a color signal is desired.

  SUMMARY OF THE INVENTION In view of the above, the present invention provides a semiconductor image sensor that simplifies a color signal arithmetic expression and improves sensitivity.

  A semiconductor image sensor according to the present invention is a semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading out signal charges of the photoelectric conversion means, wherein the first pixel and the second pixel are Alternately arranged in the horizontal direction and alternately arranged in the vertical direction, a complementary color filter is arranged in the first pixel, a primary color filter is arranged in the second pixel, and the first pixel is composed of a plurality of photoelectric conversion regions having different depths, The intersection region connecting the diagonally continuous first pixels and the diagonally continuous second pixels is a virtual pixel, and at least two first pixels and two second pixels adjacent to each other in the diagonal direction. It is characterized in that three primary color signals of virtual pixels are generated from the accumulated signal charges.

  A semiconductor image sensor according to the present invention is a semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading out signal charges of the photoelectric conversion means, wherein the first pixel and the second pixel are The first pixels are alternately arranged in the horizontal direction and alternately in the vertical direction, and the first pixels are composed of a plurality of photoelectric conversion regions having different depths, and the diagonally continuous second pixels and the diagonally continuous second pixels An intersection area connecting the virtual pixels is a virtual pixel, and three primary color signals of the virtual pixel are generated from signal charges accumulated in at least two first pixels and two second pixels that are adjacent to each other in an oblique direction. .

  A semiconductor image sensor according to the present invention is a semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading out signal charges of the photoelectric conversion means, wherein the first pixel and the second pixel are Alternately arranged in the horizontal direction and alternately arranged in the vertical direction, a complementary color filter is arranged in the first pixel, a primary color filter is arranged in the second pixel, and the first pixel is composed of a plurality of photoelectric conversion regions having different depths, A complementary color signal at the position of the second pixel is generated from the upper and lower and / or left and right first pixels of the second pixel.

  A semiconductor image sensor according to the present invention is a semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading out signal charges of the photoelectric conversion means, wherein the first pixel and the second pixel are Alternately arranged in the horizontal direction and alternately arranged in the vertical direction, a complementary color filter is arranged in the first pixel, a primary color filter is arranged in the second pixel, and the first pixel is composed of a plurality of photoelectric conversion regions having different depths, A primary color signal at the position of the first pixel is generated from the second pixel above and / or below the first pixel.

  A semiconductor image sensor according to the present invention is a semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading out signal charges of the photoelectric conversion means, wherein the first pixel and the second pixel are Alternatingly arranged in the horizontal direction and alternately in the vertical direction, the first pixel is composed of a plurality of photoelectric conversion regions having different depths, and the position of the second pixel from the upper and lower and / or left and right first pixels of the second pixel. A plurality of color signals are generated.

  A semiconductor image sensor according to the present invention is a semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading out signal charges of the photoelectric conversion means, wherein the first pixel and the second pixel are Alternatingly arranged in the horizontal direction and alternately in the vertical direction, the first pixel is composed of a plurality of photoelectric conversion regions having different depths, and the position of the first pixel from the upper and lower and / or left and right second pixels of the first pixel. The primary color signal is generated.

  The semiconductor image sensor according to the present invention is the semiconductor image sensor described above, wherein adjacent first pixels that are obliquely adjacent share a floating diffusion, and two adjacent second pixels that are obliquely continuous are defined as one. As a set, two second pixels of each set share a floating diffusion.

  In the semiconductor image sensor according to the present invention, first pixels composed of a plurality of photoelectric conversion regions having different depths and second pixels are alternately arranged in the horizontal direction and alternately in the vertical direction, and the first pixels that are obliquely continuous. An intersection area between a straight line connecting the two lines and a straight line connecting the second pixels that are obliquely continuous is defined as a virtual pixel. Further, since the three primary color signals of the virtual pixel are generated from the signal charges accumulated in at least two first pixels and two second pixels that are adjacent to each other in an oblique direction, the calculation formula for obtaining the color signal is simplified. Is planned. Further, since the first pixel is composed of a plurality of photoelectric conversion regions having different depths, the light receiving area of each pixel is widened, and the sensitivity is improved.

  In the semiconductor image sensor according to the present invention, a complementary color signal or a multi-color signal at the position of the second pixel is generated from the upper and lower and / or the left and right first pixels of the second pixel. Further, a primary color signal at the position of the first pixel is generated from the second pixel above and / or below the first pixel. With this configuration, it is possible to calculate the color signal of the pixel from the color signal of the adjacent pixel with a very simple arithmetic expression.

  Furthermore, when the photoelectric conversion regions for each color are formed at different depths and color filters corresponding to the photoelectric conversion regions are formed, it is possible to reliably separate desired color signals.

  In the semiconductor image sensor according to the present invention, adjacent pixels that are obliquely continuous share a floating diffusion, so that the light receiving area of each pixel is further increased, and the sensitivity can be further improved.

  According to the semiconductor image sensor according to the present invention, the arithmetic expression of the color signal can be simplified, so that the subsequent signal processing can be speeded up and simplified.

  Further, a configuration for generating a complementary color signal or a plurality of color signals at the position of the second pixel from the upper and lower and / or left and right first pixels of the second pixel, or from the upper and lower and / or left and right second pixels of the first pixel, When the primary color signal of the position of the first pixel is generated, the color signal can be calculated from the color signal of the adjacent pixel from the color signal of the adjacent pixel by a very simple arithmetic expression, so that the color resolution is high. The virtual pixel signal can be calculated by high-speed calculation.

  When forming a color filter, since a desired color signal can be reliably separated, color mixing in the photoelectric conversion region can be completely prevented. Therefore, excellent color reproducibility can be realized for the subject.

  Moreover, when the floating diffusion is shared in the pixel, the sensitivity can be further improved.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a schematic configuration of a semiconductor image sensor according to the first embodiment of the present invention, a so-called CMOS image sensor. The semiconductor image sensor of this embodiment is an example of color separation without using an on-chip color filter. The semiconductor image sensor 31 according to this embodiment includes an imaging region 34 formed on the surface of the same semiconductor substrate 32 and serving as a light receiving region in which a plurality of pixels 33 are two-dimensionally arranged, and outside the imaging region 34. Peripheral circuits 35 and 36 are provided for selection of the arranged pixels 33 and signal output. One peripheral circuit 35 is composed of a vertical scanning circuit (so-called vertical register circuit) located on the side of the imaging region. The other peripheral circuit 36 is a horizontal scanning circuit (so-called horizontal register circuit) and an output circuit (including a signal amplification circuit, an A / D conversion circuit, a synchronization signal generation circuit, etc.) located below the imaging region 34. Composed.

  In the imaging region 34, a plurality of pixels 33 are arranged in the vertical and horizontal directions. That is, the plurality of pixels 33 are two-dimensionally arranged in a substantially grid pattern with predetermined pitches W1 and W2 in the horizontal direction and the vertical direction, respectively, and a plurality of color component signals of different primary colors from the same pixel, two colors in this example. The first pixel 33A that detects the component signal separately and the second pixel 33B that detects a color component signal of a different primary color, in this example, one color component signal, alternately in the horizontal direction and alternately in the vertical direction. They are arranged (in a so-called checkered pattern).

  The first pixel 33A has a structure in which two primary color lights, in this example, two photodiodes that separate and photoelectrically convert blue light and red light are stacked in one pixel structure. The first pixel 33A corresponds to a so-called red / blue (R / B) pixel. The second pixel 33B has a structure in which one photodiode for photoelectrically converting one color light, in this example, green light, is formed in one pixel structure. The second pixel 33B corresponds to a so-called green (G) pixel.

  In the imaging region 34 according to the present embodiment, a straight line connecting the red / blue pixels (R / B) 33A arranged diagonally and arranged in the checkered pattern and intersecting the diagonal direction arranged in a checkered pattern. A virtual pixel 33i is formed at an intersection with a straight line connecting the green pixels (G) 33B that are obliquely continuous in the direction in which the pixels are aligned.

  FIG. 3 shows a semiconductor cross-sectional structure of the first pixel (R / B pixel) 33A. In FIG. 3, a second conductivity type semiconductor well region, in this example, a p-type semiconductor well region 42, is formed on a first conductivity type semiconductor substrate, in this example, an n-type silicon semiconductor substrate 41, and this p-type semiconductor is formed. An n-type semiconductor region 43 serving as a blue light photoelectric conversion region is formed on the surface of the well region 42 over a required width in the depth direction. In this example, the n-type semiconductor region 43 is formed over a depth of 0.1 μm to 0.3 μm in terms of depth from the surface. Further, an n-type semiconductor region 44 that becomes a photoelectric conversion region for red light is formed in a deep portion in the p-type semiconductor well region 42 over a required width in the depth direction. In this example, the n-type semiconductor region 44 is formed over a depth of 0.8 μm to 2.5 μm in terms of depth from the surface. Further, a p-type accumulation region 57 for suppressing dark current is formed so as to cover the surface of the n-type semiconductor region 43 and the surface of the region extending partly on the substrate surface side of the n-type semiconductor region 44. .

  The n-type semiconductor region 43, the p-type accumulation region 57 and the p-type semiconductor well region 42 form a photodiode PDb which is a blue photoelectric conversion means. The n-type semiconductor region 44, the p-type accumulation region 57 and the p-type accumulation region 57 A photodiode PDr which is a red photoelectric conversion means is formed by the type semiconductor well region 42. These photodiodes PDb and PDr are configured as a so-called HAD sensor (Hole Accumulation Diode) in which a p-type accumulation region 57 is formed at the interface of the substrate surface.

  In the regions on both sides of the p-type semiconductor well region 42 between the photodiodes PDb and PDr, that is, on the substrate surface side, n-type semiconductor regions 47 and 48 serving as floating diffusions FD are formed, respectively. Then, between the n-type semiconductor region 43 constituting the blue photodiode PDb on the substrate surface and the n-type semiconductor region 47 serving as one floating diffusion (FD), that is, continuously to the n-type semiconductor region 43. A gate electrode 50 is formed on the channel region 49 facing the substrate surface via a gate insulating film to form a transfer transistor Tr1b.

  Further, between the n-type semiconductor region 44 constituting the red photodiode PDr on the substrate surface and the n-type semiconductor region 48 serving as the other floating diffusion (FD), that is, continuously to the n-type semiconductor region 44. A gate electrode 52 is formed on the channel region 51 facing the substrate surface via a gate insulating film, and a transfer transistor Tr1r is formed. The first pixel 33A is separated from adjacent pixels by an isolation region formed by, for example, a selective oxide layer formed in the p-type semiconductor well region 42 or an element isolation region 54 formed by a trench isolation region.

  In this manner, the first pixel 33A has a structure in which two photodiodes PDb and PDr that separate and photoelectrically convert blue light and red light are stacked in one pixel structure. According to the first pixel 33A, the blue light having a short wavelength is photoelectrically converted by the photodiode PDb formed in the shallow region, and signal charges are accumulated in the n-type semiconductor region 43 in the shallow region. At the time of signal reading, the transfer transistor Tr1b is turned on, and the signal charge is transferred to the n-type semiconductor region 47 that becomes one floating diffusion (FD) through the channel region 49 below the one gate electrode 50. Red light having a long wavelength is photoelectrically converted by the photodiode PDr formed in a deep region, and signal charges are accumulated in the n-type semiconductor region 44 at a deep position. For signal reading, the transfer transistor Tr1r is turned on, and the signal charge is transferred through the channel region 51 below the other gate electrode 52 to the n-type semiconductor region 48 that becomes the other floating diffusion (FD).

  FIG. 2 shows a semiconductor cross-sectional structure of the second pixel (G pixel) 33B. In FIG. 2, a p-type semiconductor well region 42 of the second conductivity type is formed in the same first conductivity type n-type silicon semiconductor substrate 41 as described above. An n-type semiconductor region 56 serving as a photoelectric conversion region for green light is formed over the required depth direction width of the p-type semiconductor well region 42. That is, corresponding to the intermediate position between the n-type semiconductor region 43 and the n-type semiconductor region 44 described with reference to FIG. 3, in this example, the depth from the surface is 0.3 μm to 0.8 μm. An n-type semiconductor region 56 is formed. A p-type accumulation region 57 for suppressing dark current is formed on the surface (substrate surface) of the n-type semiconductor region 56.

  The n-type semiconductor region 56, the p-type accumulation region 57, and the p-type semiconductor well region 42 form a photodiode PDg that is a green photoelectric conversion means. This photodiode PDg is configured as a so-called HAD sensor in which a p-type accumulation region 57 is formed at the interface of the substrate surface.

  In the p-type semiconductor well region 42, an n-type semiconductor region 58 serving as a floating diffusion FD is formed. Then, between the n-type semiconductor region 56 constituting the green photodiode PDg and the n-type semiconductor region 58 serving as a floating diffusion (FD) on the substrate surface, that is, continuously to the n-type semiconductor region 58, on the substrate surface. On the facing channel region 59, a gate electrode 60 is formed through a gate insulating film to form a transfer transistor Tr1g. The second pixel 33B is separated from adjacent pixels by the element isolation region 54 similar to that described above.

  According to the second pixel 33 </ b> B, the green light is photoelectrically converted by the photodiode PDg formed in the intermediate depth region, and signal charges are accumulated in the n-type semiconductor region 56. At the time of signal readout, the transfer transistor Tr1g is turned on, and the signal charge is transferred through the channel region 59 under the gate electrode 60 to the n-type semiconductor region 58 that becomes a floating diffusion (FD).

  FIG. 4 shows a schematic configuration of a semiconductor image sensor according to a second embodiment of the present invention, a so-called CMOS image sensor. The semiconductor image sensor of this embodiment is an example in which color separation is performed using an on-chip color filter composed of complementary colors and primary colors. As the on-chip color filter of this example, two colors of on-chip color filters, a magenta (Mg) filter that is a complementary color filter and a green (G) filter that is a primary color filter, are used. In the second embodiment, portions corresponding to those in the first embodiment in FIGS. 1 to 3 are denoted by the same reference numerals.

  The semiconductor image sensor 70 according to the present embodiment is configured in the same manner as in FIG. 1 except for the on-chip color filter. That is, the imaging region 34, which is a light receiving region in which a plurality of pixels 73 formed on the surface of the same semiconductor substrate 32 are two-dimensionally arranged, and the selection and signal output of the pixels 73 disposed outside the imaging region 34 are selected. Peripheral circuits 35 and 36 for the purpose. One peripheral circuit 35 is configured by a vertical scanning circuit (so-called vertical register circuit) located on the side of the imaging region 34. The other peripheral circuit 36 is a horizontal scanning circuit (so-called horizontal register circuit) and an output circuit (including a signal amplification circuit, an A / D conversion circuit, a synchronization signal generation circuit, etc.) located below the imaging region 34. Composed.

  In the imaging region 34, a plurality of pixels 73 are arranged in the vertical and horizontal directions. That is, the plurality of pixels 73 are two-dimensionally arranged in a substantially grid pattern with predetermined pitches W1 and W2 in the horizontal direction and the vertical direction, respectively, and a plurality of color component signals of different primary colors from the same pixel, two colors in this example. The first pixel 73A that detects the component signal separately and the second pixel 73B that detects a color component signal of a different primary color, that is, one color component signal in this example, alternately in the horizontal direction and alternately in the vertical direction. They are arranged (in a so-called checkered pattern). Then, on the imaging region 34, the first pixel 73A corresponds to, for example, a magenta (Mg) filter that is a complementary color filter, and the second pixel 73B corresponds to, for example, a green (G) filter that is a primary color filter. Two on-chip color filters, a filter and a G filter, are arranged.

  In the first pixel (so-called complementary color pixel: hereinafter referred to as Mg pixel) 73A, two primary color lights, in this example, two photodiodes that separate and photoelectrically convert blue light and red light are stacked in one pixel structure. Has a structure. The second pixel (so-called primary color pixel: hereinafter referred to as G pixel) 73B has a structure in which one photodiode for photoelectrically converting one color light, in this example, green light, is formed in one pixel structure. In the imaging region 34, reference numeral 73i denotes a virtual pixel.

  FIG. 6 shows a semiconductor cross-sectional structure of the Mg pixel 73A as the first pixel. In FIG. 6, a second conductivity type semiconductor well region, in this example, a p-type semiconductor well region 42, is formed on a first conductivity type semiconductor substrate, in this example, an n-type silicon semiconductor substrate 41, as described above. Then, an n-type semiconductor region 43 serving as a blue light photoelectric conversion region is formed on the surface of the p-type semiconductor well region 42 over a required width in the depth direction. In this example, the n-type semiconductor region 43 is formed over a depth of 0.1 μm to 0.8 μm in terms of depth from the surface. Further, an n-type semiconductor region 44 that becomes a photoelectric conversion region for red light is formed in a deep portion in the p-type semiconductor well region 42 over a required width in the depth direction. In this example, the n-type semiconductor region 44 is formed over a depth of 0.8 μm to 2.5 μm in terms of depth from the surface. Further, a p-type accumulation region 57 for suppressing dark current is formed so as to cover the surface of the n-type semiconductor region 43 and the surface of the region extending partly on the substrate surface side of the n-type semiconductor region 44. .

  The n-type semiconductor region 43, the p-type accumulation region 57 and the p-type semiconductor well region 42 form a photodiode PDb which is a blue photoelectric conversion means. The n-type semiconductor region 44, the p-type accumulation region 57 and the p-type accumulation region 57 A photodiode PDr which is a red photoelectric conversion means is formed by the type semiconductor well region 42. These photodiodes PDb and PDr are configured as so-called HAD sensors in which a p-type accumulation region 57 is formed at the interface of the substrate surface.

  On the surface side of the substrate, n-type semiconductor regions 47 and 48 serving as a floating diffusion FD are formed in regions on both sides of the p-type semiconductor well region 42 between the photodiodes PDb and PDr, respectively. Then, between the n-type semiconductor region 43 constituting the blue photodiode PDb on the substrate surface and the n-type semiconductor region 47 serving as one floating diffusion (FD), that is, continuously to the n-type semiconductor region 43. A gate electrode 50 is formed on the channel region 49 facing the substrate surface via a gate insulating film to form a transfer transistor Tr1b.

  Further, between the n-type semiconductor region 44 constituting the red photodiode PDr on the substrate surface and the n-type semiconductor region 48 serving as the other floating diffusion (FD), that is, continuously to the n-type semiconductor region 44. A gate electrode 52 is formed on the channel region 51 facing the substrate surface via a gate insulating film, and a transfer transistor Tr1r is formed. The Mg pixel 73A is separated from adjacent pixels by an element isolation region 54 formed by, for example, a selective oxide layer or a trench isolation region formed in the p-type semiconductor well region 42. Then, a magenta (Mg) filter 75 of the on-chip color filters is formed on each Mg pixel 73A via a planarizing film.

  The Mg pixel 73A has a structure in which two photodiodes PDb and PDr that separate and photoelectrically convert blue light and red light that have passed through the Mg filter 75 and are incident are stacked in one pixel structure. ing. According to the Mg pixel 73, the blue light having a short wavelength transmitted through the Mg filter 75 is photoelectrically converted by the photodiode PDb formed in the shallow region, and signal charges are accumulated in the shallow n-type semiconductor region 43. At the time of signal reading, the transfer transistor Tr1b is turned on, and the signal charge is transferred to the n-type semiconductor region 47 that becomes one floating diffusion (FD) through the channel region 49 below the one gate electrode 50. The red light having a long wavelength transmitted through the Mg filter 75 is photoelectrically converted by the photodiode PDr formed in a deep region, and signal charges are accumulated in the n-type semiconductor region 44 at a deep position. At the time of signal reading, the transfer transistor Tr1r is turned on and the signal charge is transferred through the channel region 51 below the other gate electrode 52 to the n-type semiconductor region 48 that becomes the other floating diffusion (FD).

  FIG. 5 shows a semiconductor cross-sectional structure of the G pixel 73B as the second pixel. 5, a second conductivity type p-type semiconductor well region 42 is formed in the same first conductivity type n-type silicon semiconductor substrate 41 as in the configuration of FIG. 2 described above. An n-type semiconductor region 56 serving as a photoelectric conversion region for green light is formed over the required depth direction width of the p-type semiconductor well region 42. That is, as described with reference to FIG. 2, corresponding to the intermediate position between the n-type semiconductor region 43 and the n-type semiconductor region 44, in this example, the depth from the surface is 0.1 μm to 2. An n-type semiconductor region 56 is formed over a depth of 5 μm. A p-type accumulation region 57 for suppressing dark current is formed on the surface (substrate surface) of the n-type semiconductor region 56.

  The n-type semiconductor region 56, the p-type accumulation region 57, and the p-type semiconductor well region 42 form a photodiode PDg serving as a green photoelectric conversion means. This photodiode PDg is configured as a so-called HAD sensor in which a p-type accumulation region 57 is formed at the interface of the substrate surface.

  In the p-type semiconductor well region 42, an n-type semiconductor region 58 to be a floating diffusion (FD) is formed. Then, between the n-type semiconductor region 56 constituting the green photodiode PDg and the n-type semiconductor region 58 serving as a floating diffusion (FD) on the substrate surface, that is, continuously to the n-type semiconductor region 56, on the substrate surface. On the facing channel region 59, a transfer transistor Tr1g in which a gate electrode 60 is formed via a gate insulating film is formed. The G pixel 73B is separated from adjacent pixels by the element isolation region 54 as described above.

  A green (G) filter 76 among the on-chip color filters is formed on each G pixel 73B via a planarizing film.

  According to the G pixel 73B, the green light transmitted through the G filter 76 is photoelectrically converted by the photodiode PDg formed in the intermediate depth region, and signal charges are accumulated in the n-type semiconductor region 56. When the signal is read, the transfer transistor Tr1g is turned on, and the signal charge is transferred through the channel region 59 under the gate electrode 60 to the n-type semiconductor region 58 that becomes a floating diffusion (FD).

  In the above-described embodiment and the embodiments described later, although not shown, a multilayer wiring is formed above the MOS transistor constituting the pixel via an interlayer insulating film. Furthermore, an on-chip lens is formed.

  Since the semiconductor image sensors according to the first and second embodiments described above can extract the R signal and the B signal from the same pixel, as described later, the R, G, and B color signals. Can be simplified, and the signal processing at the subsequent stage can be speeded up and simplified easily.

  Next, an arithmetic expression for calculating R, G, B color signals applied to the semiconductor image sensor according to the first and second embodiments will be described with reference to FIG. Although this arithmetic expression is applied to the semiconductor image sensor of the second embodiment using Mg pixels and G pixels, it can be similarly applied to the first embodiment.

Here, prior to the description of the arithmetic expression according to the present invention, in order to facilitate understanding of the arithmetic expression of the present invention, the arithmetic expression in the case of the Bayer array that has been widely used conventionally will be described with reference to FIG. .
FIG. 24 shows a main part of a semiconductor image sensor using a Bayer type color filter. The principle of this Bayer type color filter is shown. The basic layout of the color filter starts with a red filter at the top left of the image sensor. For the color information, a virtual pixel 152 is provided in the middle surrounded by four pixels 151 [151R, 151Ga, 151Gb, 151B]. The four filtered pixels 151 around the virtual pixel 152 are two green (G) pixels (151Ga, 151Gb), one red (R) pixel (151R), and one blue (B) pixel (151B). Consists of. It can be seen that the proportion of green is large. This is because humans have good visibility against green and the filter is also balanced by giving extra light.

Attention is paid to the central virtual pixel Px which is the virtual pixel 152 in FIG. The color information PxG, PxR, PxB of the virtual pixel Px is obtained by matrix calculation from the color information of neighboring pixels. Green (G) is obtained by adding the neighboring green pixel G ₇ and pixel G ₁₀ and dividing by two. Red (R) is also considered the red information around it in preference to the red pixel R _11. Blue (B) is the same as red. In this way, the color of an arbitrary cell is specified. The calculation formula is as follows.

PxG = (G ₇ + G ₁₀ ) / 2
PxR = (9R ₁₁ + 3R ₃ + 3R ₉ + R ₁ ) / 16
PxB = (9B ₆ + 3B ₈ + 3B ₁₄ + B ₁₆ ) / 16

Here, the details of the above calculation of PxR and PxB are as follows.
For PxR, it is taken into consideration with the red pixel _{R 11,} blue pixels _{B 6,} red information of the red pixels around each of the green pixel _{G 7, G 10.}
R ₁₁
Ra (red information around the pixel B6) = (R ₁ + R ₃ + R ₉ + R ₁₁ ) / 4
Rb (red information around the pixel _{G 7) = (R 3 +} R 11) / 2
Rc (red information around the pixel _{G 10) = (R 9 +} R 11) / 2
∴PxR = (Ra + Rb + Rc + R ₁₁ ) / 4
= [{(R ₁ + R ₃ + R ₉ + R ₁₁ ) / 4}
+ {(R ₃ + R ₁₁ ) / 2}
+ {(R ₉ + R ₁₁ ) / 2}
+ R ₁₁ ] / 4
= (R ₁ + R ₃ + R ₉ + R ₁₁ + 2R ₃ + 2R ₁₁ + 2R ₉ + 2R ₁₁
+ 4R ₁₁ ) / 16
= (9R ₁₁ + 3R ₃ + 3R ₉ + R ₁ ) / 16

For PxB, blue information of the blue pixel B ₆ and the blue pixels around each of the green pixels G ₇ and G ₁₀ is added.
B ₆
Ba (blue information around the pixel _{R 11) = (B 6 +} B 8 + B 14 + B 16) / 4
Bb (blue information about the pixel _{G 7) = (B 6 +} B 8) / 2
Bc (blue information around the pixel _{G 10) = (B 6 +} B 14) / 2
∴PxB = (Ba + Bb + Bc + B ₆ ) / 4
= [{(B ₆ + B ₈ + B ₁₄ + B ₁₆ ) / 4}
+ {(B ₆ + B ₈ ) / 2}
{(B ₆ + B ₁₄ ) / 2}
+ B ₆ ] / 4
= (B ₆ + B ₈ + B ₁₄ + B ₁₆ + 2B ₆ + 2B ₈ + 2B ₆ + 2B ₁₄
+ 4B ₆ ) / 16
= (9B ₆ + 3B ₈ + 3B ₁₄ + B ₁₆ ) / 16
This calculation method is an epoch-making method that allows easy coloring.

Next, an arithmetic expression according to the present embodiment will be described.
First, the arithmetic expression of 2nd Embodiment (refer FIG. 4) is demonstrated. As shown in FIG. 7, horizontal and vertical 2 × 2 pixels, that is, regions (crossing regions of four pixels) extending over two G pixels and two Mg pixels are assumed to be virtual pixels P1 to P9. Now, the green (G), red (R), and blue (B) color signals G _{P5 of the} virtual pixel P5 straddling the two G pixels [pixels G11 and G22] and the two Mg pixels [pixels Mg12 and Mg21]. , R _P5 and B _P5 are calculated.
G ₁₁ and G ₂₂ are the green component signals of the pixels G11 and G22, Mg _12B and Mg _21B are the blue component signals of the pixels Mg12 and Mg21, respectively, and Mg _12R and Mg _21R are the red component signals of the pixels Mg12 and Mg21, respectively.

The green (G), red (R), and blue (B) color signals G _P5 , R _P5 , and B _P5 of the virtual pixel P5 are obtained by an arithmetic expression represented by the following equation (1).

[Equation 1]
G _P5 = (G ₁₁ + G ₂₂ ) / 2
R _P5 = (Mg _21R + Mg _12R ) / 2
B _P5 = (Mg _21B + Mg _12B ) / 2

The arithmetic expression of 1st Embodiment (refer FIG. 1) is demonstrated. In the first embodiment, Mg in FIG. 7 is replaced with R / B. That is, G11, G11, Mg12, and Mg22 are replaced with G11, G22, R / B12, and R / B22. As a result, the green (G), red (R), and blue (B) color signals G _P5 , R _P5 , and B _P5 of the virtual pixel P5 are obtained by an arithmetic expression represented by the following equation (2).

[Equation 2]
G _P5 = (G ₁₁ + G ₂₂ ) / 2
R _P5 = (R / B _21R + R / B _12R ) / 2
B _P5 = (R / B _21B + R / B _12B ) / 2

  As described above, in the first and second embodiments of the present invention, the R signal and the B signal can be extracted from the same pixel. The arithmetic expression can be simplified. This facilitates speeding up and simplifying subsequent signal processing.

Furthermore, according to the semiconductor image sensor 31 according to the first embodiment, the imaging region is formed by the arrangement of the first pixel (R / B pixel) and the second pixel (G pixel). The light receiving area can be increased, and the sensitivity can be improved.
Since the photodiodes PDb, PDr, and PDg constituting the first pixel 33A and the second pixel 33B have the HAD structure, generation of noise can be remarkably suppressed. In particular, even if the reset operation is performed in the R / B pixel 33A, noise does not occur in the n-type semiconductor regions 44 and 43, which are red (R) and blue (B) charge storage regions. Therefore, S / N is improved.

  The first pixel 33A and the second pixel 33B have a configuration in which the positions in the depth direction of the n-type semiconductor regions 43, 44, and 56 that contribute to photoelectric conversion of light of different colors are different according to the wavelength. As a result, color mixing is suppressed and color separation is enhanced.

Further, according to the semiconductor image sensor 70 of the second embodiment, since the imaging region is formed by the arrangement of the G pixel and the Mg pixel, the light receiving area of each pixel can be widened, and the sensitivity is improved. be able to.
Since the photodiodes PDb, PDr, and PDg constituting the Mg pixel 73A and the G pixel 73B have a HAD structure, generation of noise can be remarkably suppressed. In particular, even if the reset operation is performed in the Mg pixel 73A, noise does not occur in the n-type semiconductor regions 44 and 43 that are red (R) and blue (B) charge storage regions. Therefore, S / N is improved. In the Mg pixel 73A and the G pixel 73B, the positions in the depth direction of the n-type semiconductor regions 43, 44, and 56 that contribute to photoelectric conversion of light of different colors are different depending on the wavelength. Color mixing is suppressed, and color separation is improved.

  By using two on-chip color filters, magenta (Mg), which is a complementary color filter, and green (G), which is a primary color filter, light is absorbed by the filter compared to a photodiode using a primary color filter. Since it can be suppressed, the sensitivity does not decrease. The cross-sectional structure of the sensor to be detected, that is, the photodiode is substantially the same as that of the first embodiment without the on-chip color filter. However, since the on-chip color filter is used, the width of the depth of the n-type semiconductor region is reduced. Roughly designed. For example, as described above, the n-type semiconductor region 56 serving as a green light photoelectric conversion region can be formed with a width of 0.1 μm to 2.5 μm, and the n-type semiconductor region serving as a blue light photoelectric conversion region. The depth of 43 can be formed with a width of 0.1 to 0.8 μm, and the width of the n-type semiconductor region 44 serving as a red light photoelectric conversion region can be formed with a width of 0.8 to 2.5 μm. it can. When forming a color filter, a desired color signal can be reliably separated.

In the first embodiment and the second embodiment, the intersection area connecting the straight line connecting the first pixels that are obliquely connected to the second pixel is the virtual pixels 33i, 73i, and the color signals of the virtual pixels 33i, 73i Equations 2 and 1 are shown as equations for calculating.
A semiconductor image sensor using an arithmetic expression for calculating R, G, B color signals of pixels without setting virtual pixels will be described below.

A semiconductor image sensor according to a third embodiment of the present invention will be described with reference to FIGS.
FIGS. 8 and 9 show the image pickup region 34 constituting the semiconductor image sensor 31 in the first embodiment for the purpose of explaining the present embodiment. Other configurations are the same as those in FIG.
The semiconductor image sensor according to the present embodiment has the same configuration as that of the semiconductor image sensor according to the first embodiment, but has different arithmetic expressions for calculating the color signals of pixels used in the semiconductor image sensor.

First, in the present embodiment, an arithmetic expression for calculating the color signal of the first pixel 33A will be described.
As shown in FIG. 8, R / B pixels located at the top, bottom, left, and right with respect to the pixel G23 around the pixel G23 that is the G pixel constituting the second pixel 33B are the pixel R / B13, the pixel R / B33, The pixel R / B22, the pixel R / B24, and the G pixel diagonally adjacent to each other are referred to as a pixel G12, a pixel G14, a pixel G32, and a pixel G34.
Here, the pixel G12, G14, G23, G32, the green component signal of the G34 and _{G 12, G 14, G 23} , G 32, G 34, the pixel R / B13, R / B22, R / B24, R / B33 R / B ₁₃ R, R / B ₂₂ R, R / B ₂₄ R, R / B ₃₃ R, and blue component signals R / B ₁₃ B, R / B ₂₂ B, R / B ₂₄ B , R / B ₃₃ B.

The green (G), red (R), and blue (B) color signals G _g23 , R _g23 , and B _g23 of the pixel G23 are _obtained by the following arithmetic expressions.
First, when the upper and lower pixels of the pixel G23 are used in the arithmetic expression, the arithmetic expression shown in Equation 2 is obtained.

[Equation 3]
G _g23 = G ₂₃
R _g23 = (R / B ₁₃ R + R / B ₃₃ R) / 2
B _g23 = (R / B ₁₃ B + R / B ₃₃ B) / 2

  Further, when the left and right pixels of the pixel G23 are used in the arithmetic expression, the arithmetic expression shown in Expression 3 is obtained.

[Equation 4]
G _g23 = G ₂₃
R _g23 = (R / B ₂₂ R + R / B ₂₄ R) / 2
B _g23 = (R / B ₂₂ B + R / B ₂₄ B) / 2

  Further, when the upper, lower, left, and right pixels of the pixel G23 are used in the arithmetic expression, the arithmetic expression shown in Expression 4 is obtained.

[Equation 5]
G _g23 = G ₂₃
R _g23 = (R / B ₁₃ R + R / B ₃₃ R + R / B ₂₂ R + R / B ₂₄ R) / 4
B _g23 = (R / B ₁₃ B + R / B ₃₃ B + R / B ₂₄ B + R / B ₂₄ B) / 4

Next, an arithmetic expression for calculating the color signal of the first pixel 33A in the present embodiment will be described. As shown in FIG. 9, the G pixel, which is the first pixel 33A, is located at the top, bottom, left, and right with respect to the pixel R / B22 with the pixel R / B22 being the R / B pixel constituting the first pixel 33A as the center. Pixels G12, G32, G21, and G23, and R / B pixels that are second pixels 33B that are obliquely adjacent to each other are referred to as pixels R / B11, R / B13, R / B31, and R / B33.
Here, the green component signal of the pixel G12, G21, G23, G32 and _{G 12, G 21, G 23} , G 32, the pixel R / B11, R / B13, R / B22, R / B31, R / B33 The red component signal is R / B ₁₁ R, R / B ₁₃ R, R / B ₂₂ R, R / B ₃₁ R, R / B ₃₃ R, and the blue component signal is R / B ₁₁ B, R / B ₁₃ B, R / B ₂₂ B, R / B ₃₁ B, R / B ₃₃ B.

The green (G), red (R), and blue (B) color signals G _rb22 , R _rb22 , and B _rb22 of the pixel R / B 22 are _obtained by the following arithmetic expressions (6 to 8).
First, when the upper and lower pixels of the pixel R / B 22 are used in the arithmetic expression, the arithmetic expression shown in Expression 6 is obtained.

[Equation 6]
G _rb22 = (G ₁₂ + G ₃₂ ) / 2
R _rb22 = R / B ₂₂ R
B _rb22 = R / B ₂₂ B

  Further, when the left and right pixels of the pixel R / B 22 are used in the arithmetic expression, the arithmetic expression shown in Expression 7 is obtained.

[Equation 7]
G _rb22 = (G ₂₁ + G ₂₃ ) / 2
R _rb22 = R / B ₂₂ R
B _rb22 = R / B ₂₂ B

  In addition, when the upper, lower, left, and right pixels of the pixel R / B 22 are used in the arithmetic expression, the arithmetic expression shown in Expression 8 is obtained.

[Equation 8]
G _rb22 = (G ₁₂ + G ₃₂ + G ₂₁ + G ₂₃ ) / 4
R _rb22 = R / B ₂₂ R
B _rb22 = R / B ₂₂ B

As described above, in the third embodiment, a pixel from which a signal is extracted can be selected up and down or / and left and right, and the pixel can be calculated using an optimal calculation formula.
In the third embodiment, since the R signal and the B signal can be extracted from the same pixel, the arithmetic expressions of the R, G, and B color signals can be simplified as shown in Equations (3) to (8). Can do. This facilitates speeding up and simplifying subsequent signal processing.
Further, since the arithmetic expression is simplified, even when the pixel has a defect, the arithmetic expression for complementing the R, G, B color signals in the defective pixel becomes easy.

Next, a semiconductor image sensor according to a fourth embodiment of the present invention will be described with reference to FIGS.
FIGS. 10 and 11 illustrate the imaging region 34 constituting the semiconductor image sensor in the second embodiment, for the purpose of explaining the present embodiment. Other configurations are the same as those in FIG.
The semiconductor image sensor in the present embodiment has the same configuration as that of the semiconductor image sensor in the second embodiment, but the calculation formula for calculating the color signal of the pixel used in the semiconductor image sensor is different.

First, in the present embodiment, an arithmetic expression for calculating the color signal of the first pixel will be described.
As shown in FIG. 10, the Mg pixel located at the top, bottom, left, and right with respect to the pixel G23 centered on the pixel G23 that constitutes the second pixel is the pixel Mg13, the pixel Mg33, the pixel Mg22, the pixel Mg24, G pixels adjacent to the pixel G12 are referred to as a pixel G12, a pixel G14, a pixel G32, and a pixel G34.
Here, the pixel G12, G14, G23, G32, the green component signal of the G34 and _{G 12, G 14, G 23} , G 32, G 34, pixel Mg13, Mg22, Mg24, the red component signal of Mg33 _{Mg 13} R , Mg ₂₂ R, Mg ₂₄ R, Mg ₃₃ R, and the blue component signals are Mg ₁₃ B, Mg ₂₂ B, Mg ₂₄ B, and Mg ₃₃ B.

The green (G), red (R), and blue (B) color signals G _g23 , R _g23 , and B _g23 of the pixel G23 are _obtained by the following arithmetic expressions.
First, when the pixels above and below the pixel G23 are used in the arithmetic expression, the arithmetic expression shown in Equation 9 is obtained.

[Equation 9]
G _g23 = G ₂₃
R _g23 = (Mg ₁₃ R + Mg ₃₃ R) / 2
B _g23 = (Mg ₁₃ B + Mg ₃₃ B) / 2

  Further, when the left and right pixels of the pixel G23 are used in the arithmetic expression, the arithmetic expression shown in Expression 10 is obtained.

[Equation 10]
G _g23 = G ₂₃
R _g23 = (Mg ₂₂ R + Mg ₂₄ R) / 2
B _g23 = (Mg ₂₂ B + Mg ₂₄ B) / 2

  Further, when the upper, lower, left, and right pixels of the pixel G23 are used in the arithmetic expression, the arithmetic expression shown in Expression 11 is obtained.

[Equation 11]
G _g23 = G ₂₃
R _g23 = (Mg ₁₃ R + Mg ₃₃ R + Mg ₂₂ R + Mg ₂₄ R) / 4
B _g23 = (Mg ₁₃ B + Mg ₃₃ B + Mg ₂₄ B + Mg ₂₄ B) / 4

Next, an arithmetic expression for calculating the color signal of the first pixel in this embodiment will be described. As shown in FIG. 11, the pixels G12, G32, G21, and G23 are pixels G12, G32, G21, and G23 that are centered on the pixel Mg22 that constitutes the first pixel, and that are the first pixels that are positioned vertically and horizontally with respect to the pixel Mg22. The Mg pixels that are the second pixels obliquely adjacent to each other are designated as pixels Mg11, Mg13, Mg31, and Mg33.
Here, the pixel G12, G21, G23, the green component signal of the G32 and _{G 12, G 21, G 23} , G 32, pixel Mg11, Mg13, Mg22, Mg31, Mg33 of the red component signal _Mg 11R, _{Mg 13} R , Mg ₁₂ R, Mg ₃₁ R, Mg ₃₃ R, and the blue component signals are Mg ₁₁ B, Mg ₁₃ B, Mg ₂₂ B, Mg ₃₁ B, and Mg ₃₃ B.

The green (G), red (R), and blue (B) color signals G _Mg22 , R _Mg22 , and B _Mg22 of the _{pixel Mg22} are _obtained by the following arithmetic expressions (12 to 14).
First, when the upper and lower pixels of the pixel Mg22 are used in the arithmetic expression, the arithmetic expression shown in Expression 12 is obtained.

[Equation 12]
G _Mg22 = (G ₁₂ + G ₃₂ ) / 2
R _Mg22 = Mg ₂₂ R
B _Mg22 = Mg ₂₂ B

  Further, when the left and right pixels of the pixel Mg22 are used in the arithmetic expression, the arithmetic expression shown in Expression 13 is obtained.

[Equation 13]
G _Mg22 = (G ₂₁ + G ₂₃ ) / 2
R _Mg22 = Mg ₂₂ R
B _Mg22 = Mg ₂₂ B

  Further, when the upper, lower, left, and right pixels of the pixel Mg22 are used in the arithmetic expression, the arithmetic expression shown in Expression 14 is obtained.

[Formula 14]
_{G Mg22 = (G 12 + G} 32 + G 21 + G 23) / 4
R _Mg22 = Mg ₂₂ R
B _Mg22 = Mg ₂₂ B

As described above, in the fourth embodiment, a pixel from which a signal is extracted can be selected up and down or / and left and right, and the pixel can be calculated using an optimal calculation formula.
In the fourth embodiment, since the R signal and the B signal can be extracted from the same pixel, the arithmetic expressions of the R, G, and B color signals can be simplified as shown in the equations 9 to 14. Can do. This facilitates speeding up and simplifying subsequent signal processing.
Further, since the arithmetic expression is simplified, even when the pixel has a defect, the arithmetic expression for complementing the R, G, B color signals in the defective pixel becomes easy.

  12 to 16 show a schematic configuration of a semiconductor image sensor according to the fifth embodiment of the present invention, a so-called CMOS image sensor. The semiconductor image sensor according to the present embodiment is an example in which floating diffusion (FD) of adjacent pixels is shared and color separation is performed without using an on-chip color filter. In the figure, parts corresponding to those in FIGS. 1 to 3 are denoted by the same reference numerals.

  As shown in FIG. 12, in the semiconductor image sensor 80 according to the present embodiment, a plurality of pixels 83 formed on the surface of the same semiconductor substrate 32 are two-dimensionally arranged as in the above-described embodiment. The image pickup area 34 is a light receiving area, and peripheral circuits 35 and 36 are provided for selection and signal output of the pixels 83 arranged outside the image pickup area 34. One peripheral circuit 35 is composed of a vertical scanning circuit (so-called vertical register circuit) located on the side of the imaging region. The other peripheral circuit 36 is a horizontal scanning circuit (so-called horizontal register circuit) and an output circuit (including a signal amplification circuit, an A / D conversion circuit, a synchronization signal generation circuit, etc.) located below the imaging region 34. Composed.

  In the imaging region 34, a plurality of pixels 83 are arranged in the vertical and horizontal directions. That is, the plurality of pixels 83 are two-dimensionally arranged in a substantially grid pattern with predetermined pitches W1 and W2 in the horizontal direction and the vertical direction, respectively, and a plurality of color component signals of different primary colors from the same pixel, two colors in this example. The first pixel 83A that detects the component signals separately and the second pixel 83B that detects the color component signals of different primary colors, in this example, one color component signal, alternately in the horizontal direction and alternately in the vertical direction. They are arranged (in a so-called checkered pattern).

  The first pixel 83A has a structure in which two photodiodes that separate and photoelectrically convert two primary color lights, in this example, blue light and red light, are stacked in one pixel structure. The first pixel 83A corresponds to a so-called red / blue (R / B) pixel. The second pixel 83B has a structure in which one photodiode for photoelectrically converting one color light, in this example, green light, is formed in one pixel structure. The second pixel 83B corresponds to a so-called green (G) pixel.

In the present embodiment, the floating diffusion (FD) of two adjacent first pixels 83A arranged in the checkered pattern and obliquely continuous is shared. In this case, as will be apparent later, one adjacent two first pixels share, for example, a floating diffusion FD2 used for transferring a red signal charge, and the other two adjacent second pixels are For example, the floating diffusion FD3 used for transferring the blue signal charge is shared.
In addition, the floating diffusion (FD) of the second pixel (G pixel) 83 </ b> B arranged in a checkered pattern and arranged in a diagonally continuous pair is shared. That is, in this case, as will be described later, in the second pixels 83B that are obliquely continuous, every other adjacent second pixel shares the floating diffusion FD1.

  In the imaging region 34, as in the first and second embodiments, although not shown, a straight line connecting the red / blue pixels (R / B) 83A arranged in the checkered pattern and obliquely continuous, Virtual pixels are formed at the intersections with straight lines that are arranged in a checkered pattern and obliquely continue in the direction intersecting the oblique direction.

  FIG. 15 is a schematic plan view of an essential part of an enlarged first pixel (R / B) 83A that is obliquely continuous in FIG. FIG. 16 shows a semiconductor cross-sectional structure of the first pixel (R / B pixel) 83A on the BB line in FIG. In FIG. 15, two adjacent pixels that are obliquely continuous share one floating diffusion FD2, FD3. That is, the pixels R / B 14 and R / B 23, the pixels R / B 23 and R / B 32, and the pixels R / B 32 and R / B 41, which are first pixels adjacent to each other that are diagonally continuous, are alternately shared. The transfer gate electrodes 50 and 52 are formed between the photodiodes and the floating diffusions FD2 and FD3, respectively, with the diffusions FD2 and FD3 interposed therebetween.

  In FIG. 16, the configuration of one first pixel (R / B pixel) 83A is substantially the same as that of FIG. 3 described above.

  In the present embodiment, as shown in FIG. 16, two adjacent first pixels R / B14 and R / B23, R / B23 and R / B32, and R / B32 that are adjacent to each other, which are diagonally continuous. And the pixel R / B 41, that is, the photodiodes PDr and the transfer gate electrode 52, the photodiodes PDb and the transfer gate electrode 50, and the floating diffusions FD2 and FD3 shared by each other, are formed symmetrically.

  In the two adjacent first pixels, for example, the pixel R / B14 and the pixel R / B23, the red signal charges that are photoelectrically converted and accumulated by the photodiode PDr are respectively transferred to the transfer gate electrodes with a predetermined timing difference. 52 is transferred to the shared floating diffusion FD2. Further, for example, in the pixel R / B 23 and the pixel R / B 32, the blue signal charges that are photoelectrically converted and accumulated by the photodiode PDb are turned on and shared with a predetermined timing difference, respectively. It is transferred to the floating diffusion FD3. The same applies hereinafter.

  FIG. 13 is a schematic plan view of a main part in which the second pixels (G pixels) 83B that are obliquely continuous in FIG. 12 are enlarged. FIG. 14 shows a semiconductor cross-sectional structure of the second pixel (G pixel) 83B on the AA line in FIG. In FIG. 13, two adjacent second pixels 83 </ b> B that are obliquely adjacent to each other are taken as one set, and two second pixels 83 </ b> B of each set share one floating diffusion FD <b> 1. That is, the photodiodes of the two second pixels 83B are arranged with the floating diffusion FD1 sandwiched therebetween, and the gate electrodes (so-called transfer gate electrodes) of the transfer transistors are provided between the photodiodes and the floating diffusion FD1. 60 is formed.

  In FIG. 14, the configuration of one second pixel (G pixel) 83B is substantially the same as that of FIG. 2 described above, and therefore, the corresponding parts are denoted by the same reference numerals and redundant description is omitted.

  In the present embodiment, as shown in FIG. 14, two adjacent second pixels 83B (that is, the pixel G24) and second pixel 83B (that is, the pixel G33) that are adjacent obliquely, that is, the respective photodiodes PDg and transfer gates. The electrodes 60 are formed in a symmetrical relationship across the floating diffusion FD1 shared. Similarly, the two adjacent second pixels 83B (that is, the pixel G42) and the second pixel 83B (that is, the pixel G51) that are obliquely continuous are formed in a symmetrical relationship with the floating diffusion FD1 shared therebetween.

  In this pair of second pixels 83B, for example, the pixel G24 and the pixel G33, the signal charges that are photoelectrically converted and accumulated by the respective photodiodes PDg are placed at different timings, and the transfer gate electrodes 60 are respectively set. Turned on and transferred to the shared floating diffusion FD1.

  17 to 21 show a schematic configuration of a semiconductor image sensor according to the sixth embodiment of the present invention, a so-called CMOS image sensor. The semiconductor image sensor of this embodiment is an example in which color separation is performed using an on-chip color filter composed of complementary colors and primary colors. As the on-chip color filter of this example, two colors of on-chip color filters, a magenta (Mg) filter that is a complementary color filter and a green (G) filter that is a primary color filter, are used. In the fourth embodiment, parts corresponding to those in the second embodiment in FIGS. 4 to 6 are described with the same reference numerals.

  The semiconductor image sensor 90 according to the present embodiment is configured in the same manner as in FIG. 12 except for the on-chip color filter. That is, the semiconductor image sensor 90 according to the present embodiment includes an imaging region 34 that is a light receiving region in which a plurality of pixels 93 formed on the surface of the same semiconductor substrate 32 are two-dimensionally arranged, and the imaging region 34. Peripheral circuits 35 and 36 for selecting and outputting signals of the pixels 93 arranged outside are provided. One peripheral circuit 35 is configured by a vertical scanning circuit (so-called vertical register circuit) located on the side of the imaging region 34. The other peripheral circuit 36 is a horizontal scanning circuit (so-called horizontal register circuit) and an output circuit (including a signal amplification circuit, an A / D conversion circuit, a synchronization signal generation circuit, etc.) located below the imaging region 34. Composed.

  In the imaging region 34, a plurality of pixels 93 are arranged in the vertical and horizontal directions. That is, the plurality of pixels 93 are two-dimensionally arranged in a substantially grid pattern with predetermined pitches W1 and W2 in the horizontal direction and the vertical direction, respectively, and a plurality of color component signals of different primary colors from the same pixel, two colors in this example. The first pixel 93A for separating and detecting the component signals and the second pixel 93B for detecting the color component signals of different primary colors, one color component signal in this example, alternately in the horizontal direction and alternately in the vertical direction. (So-called checkered pattern) is arranged. Then, on the imaging region 34, the first pixel 93A corresponds to, for example, a magenta (Mg) filter that is a complementary color filter, and the second pixel 93B corresponds to, for example, a green (G) filter that is a primary color filter. Two on-chip color filters, a filter and a G filter, are arranged.

  The first pixel (so-called complementary color pixel: hereinafter referred to as Mg pixel) 93A has two photodiodes that separate and photoelectrically convert two primary color lights, blue light and red light in this example, in one pixel structure. Has a structure. The second pixel (so-called primary color pixel: hereinafter referred to as G pixel) 93B has a structure in which one photodiode for photoelectrically converting one color light, in this example, green light, is formed in one pixel structure.

In the present embodiment, the floating diffusion (FD) of two adjacent first pixels 93A arranged in a checkered pattern and obliquely continuous is shared. In this case, as will be apparent later, one adjacent two first pixels share, for example, a floating diffusion FD2 used for transferring a red signal charge, and the other two adjacent second pixels are For example, the floating diffusion FD3 used for transferring the blue signal charge is shared.
Also, the floating diffusion (FD) of the second pixels (G pixels) 93B arranged in a checkered pattern and arranged in a diagonally continuous pair is configured. That is, in this case, as will be described later, in the second pixels 93B that are obliquely continuous, every other adjacent second pixel is configured to share the floating diffusion FD1.

  Although not shown in the drawing area 34 as described above, a straight line connecting the complementary color pixels (Mg pixels) 83A arranged in the checkered pattern and diagonally continuous, and the diagonal direction arranged in the checkered pattern Virtual pixels are formed at the intersections with the straight lines connecting the green pixels (G pixels) 93B that are obliquely continuous in the intersecting direction.

  FIG. 20 is a schematic plan view of a main part in which the first pixels (Mg pixels) 93A that are obliquely continuous in FIG. 17 are enlarged. FIG. 21 shows a semiconductor cross-sectional structure of the first pixel (Mg pixel) 93A on the BB line in FIG. In FIG. 20, two adjacent first pixels that are obliquely continuous share one floating diffusion FD2, FD3. That is, pixels Mg14 and Mg23, which are diagonally adjacent first pixels, pixel Mg23 and pixel Mg32, and pixel Mg32 and pixel Mg41 are arranged sandwiching floating diffusions FD2 and FD3 that are alternately shared. At the same time, transfer gate electrodes 50 and 52 are formed between the photodiodes and the floating diffusions FD2 and FD3, respectively.

  In FIG. 21, the configuration of one first pixel (Mg pixel) 93A is substantially the same as that of FIG. 6 described above, and therefore the corresponding parts are denoted by the same reference numerals and redundant description is omitted.

  In the present embodiment, as shown in FIG. 21, two adjacent first pixels that are obliquely adjacent, the pixel Mg14 and the pixel Mg23, the pixel Mg23 and the pixel Mg32, the pixel Mg32 and the pixel Mg41, that is, the respective photodiodes PDr. Further, the floating gate electrodes 52, the photodiode PDb, and the transfer gate electrode 50 are formed in a symmetrical relationship with the floating diffusions FD2 and FD3 shared therebetween.

  In these two adjacent first pixels, for example, the pixel Mg14 and the pixel Mg23, the red signal charges accumulated by photoelectric conversion by the photodiode PDr respectively turn on the transfer gate electrode 52 with a predetermined timing difference. And transferred to the shared floating diffusion FD2. Further, for example, in the pixel Mg23 and the pixel Mg32, the floating signal diffusion in which the blue signal charges photoelectrically converted and accumulated by the photodiode PDb are turned on and shared with a predetermined timing difference, respectively. Transferred to FD3. The same applies hereinafter.

  FIG. 18 is a schematic plan view of an essential part of an enlarged second pixel (G pixel) 93B that is obliquely continuous in FIG. FIG. 19 shows a semiconductor cross-sectional structure of the second pixel (G pixel) 93B on the AA line in FIG. In FIG. 18, two adjacent second pixels 93B that are obliquely continuous are taken as one set, and two second pixels 93B in each set share one floating diffusion FD1. That is, the photodiodes of the two second pixels 93B are arranged with the floating diffusion FD1 interposed therebetween, and the gate electrodes (so-called transfer gate electrodes) of the transfer transistors are provided between the photodiodes and the floating diffusion FD1. 60 is formed.

  In FIG. 19, the configuration of one second pixel (G pixel) 93 </ b> B is generally the same as that of FIG. 5 described above, and therefore the corresponding parts are denoted by the same reference numerals and redundant description is omitted.

  In the present embodiment, as shown in FIG. 19, two adjacent second pixels 93B (that is, the pixel G24) and second pixel 83B (that is, the pixel G33) that are obliquely continuous, that is, the respective photodiodes PDg and transfer gates. The electrodes are formed in a symmetrical relationship across the floating diffusion FD1 shared by the electrodes. Similarly, two adjacent second pixels 93B (that is, the pixel G42) and the second pixel 93B (that is, the pixel G51) that are adjacent to each other obliquely are formed in a symmetrical relationship with the floating diffusion FD1 shared therebetween.

  In the second set of second pixels 93B, for example, the pixel G24 and the pixel G33, the signal charges that have been photoelectrically converted and accumulated by the respective photodiodes PDg are transferred to the respective transfer gate electrodes 60 with a required timing difference. It is transferred to the floating diffusion FD1 that is turned on and shared.

The color signals in the fifth embodiment and the sixth embodiment described above can be obtained using the arithmetic expression shown in Equation 1 above. That is, for example, in FIG. 17, a region (intersection region of four pixels) straddling two G pixels and two Mg pixels which are horizontal and vertical 2 × 2 pixels is set as a virtual pixel. Now, the green (G), red (R) and blue (B) color signals G _P5 , R _P5 and B _P5 of the virtual pixel P5 straddling the pixels G11, G22, Mg12 and Mg21 are calculated.

As before,
[Equation 15]
G _P5 = (G ₁₁ + G ₂₂ ) / 2
R _P5 = (Mg _21R + Mg _12R ) / 2
B _P5 = (Mg _21B + Mg _12B ) / 2
It is obtained by.

  In FIG. 12, G11, G22, Mg12, and Mg21 in the above-described arithmetic expressions are replaced with G11, G22, R / B12, and R / B21 to similarly obtain each color signal of the R signal, the G signal, and the B signal. Can do.

  As described above, in the fifth and sixth embodiments of the present invention, since the R signal and the B signal can be extracted from the same pixel, the arithmetic expressions of the R, G, and B color signals are simplified as described above. can do. This facilitates speeding up and simplifying subsequent signal processing.

Furthermore, according to the semiconductor image sensor 80 according to the fifth embodiment, two adjacent pixels of the same color that are adjacent to each other in an array of the first pixel (R / B pixel) and the second pixel (G pixel). Since they share the floating diffusion (FD), the light receiving area of each pixel can be increased and the sensitivity can be improved.
Since the photodiodes PDb, PDr, and PDg constituting the first pixel 83A and the second pixel 83B have an HAD structure, generation of noise can be remarkably suppressed. In particular, even if the reset operation is performed in the R / B pixel 83A, noise does not occur in the n-type semiconductor regions 44 and 43 that are red (R) and blue (B) charge storage regions. Therefore, S / N is improved.

  The first pixel 83A and the second pixel 83B have a configuration in which the positions in the depth direction of the n-type semiconductor regions 43, 44, and 56 that contribute to photoelectric conversion of light of different colors are different according to the wavelength. As a result, color mixing is suppressed and color separation is enhanced.

In addition, according to the semiconductor image sensor 90 according to the sixth embodiment, two adjacent pixels of the same color that are diagonally continuous in an array of the first pixel (Mg pixel) and the second pixel (G pixel) are floating. Since the diffusion (FD) is shared, the light receiving area of each pixel can be increased and the sensitivity can be improved.
Since the photodiodes PDb, PDr, and PDg constituting the first pixel 93A and the second pixel 93B have the HAD structure, generation of noise can be remarkably suppressed. In particular, even if the reset operation is performed in the Mg pixel 93A, noise does not occur in the n-type semiconductor regions 44 and 43 that are red (R) and blue (B) charge storage regions. Therefore, S / N is improved.

  In the first pixel 93A and the second pixel 93B, the positions in the depth direction of the n-type semiconductor regions 43, 44, and 56 that contribute to the photoelectric conversion of the light of each color having different wavelengths are different depending on the wavelength. As a result, color mixing is suppressed and color separation is enhanced. When forming a color filter, a desired color signal can be reliably separated.

  On the other hand, the semiconductor image sensor according to the present invention can share the MOS transistors constituting the pixels in the plurality of pixels of the first pixel group and the second pixel group. That is, in the case of four MOS transistors, for example, the selection transistor, the reset transistor, the amplification transistor, or all of these transistors can be shared. In the case of three MOS transistors, each of the reset transistor and the amplification transistor, or all of these transistors can be shared.

The embodiment is shown in FIG. 22 and FIG. FIG. 22 shows an embodiment in which an amplification transistor, a reset transistor, and a selection transistor are shared by two pixels of the Mg pixel and the G pixel. In the present embodiment, the sources of the transfer transistors Tr1g, Tr1r, Tr1b corresponding to the green photodiode PDg by the G pixel and the red photodiode PDr and the blue photodiode PDb by the Mg pixel are respectively connected. The Transfer wirings 111 (G), 111 (MgR), and 111 (MgB) are connected to the gates of the transfer transistors Tr1g, Tr1r, and Tr1b. The drains of the transfer transistors Tr1g, Tr1r, Tr1b are connected in common and connected to one reset transistor Tr _RES , and a so-called floating diffusion FD between the drain of the transfer transistor and the source of the reset transistor is amplified by one. Connected to the gate of the transistor Tr _AMP . The drain of the reset transistor Tr _{RES and} the drain of the amplification transistor Tr _AMP are connected to the power supply wiring 112 (Vcc). The gate of the reset transistor Tr _RES is connected to the reset wiring 113. Further, the source of the amplification transistor Tr _AMP is connected to the drain of one selection transistor Tr _SEL . The source of the selection transistor Tr _SEL is connected to the vertical signal line 115 and the selection wiring 114 is connected to the gate thereof.

Thus, by sharing the reset transistor Tr _RES , the amplification transistor Tr _AMP and the selection transistor Tr _SEL with respect to the two pixels of the Mg pixel and the G pixel, the Mg pixel and the G pixel described above are arranged obliquely. In addition to the effect, the area of the MOS transistor of the pixel can be reduced. Accordingly, since the photodiode area (opening area of the light receiving portion) can be further increased, the saturation charge amount and sensitivity can be further improved.

FIG. 23 shows an embodiment in which an amplification transistor, a reset transistor, and a selection transistor are shared by a total of four pixels including two Mg pixels and two G pixels. In the present embodiment, transfer transistors respectively corresponding to green photodiodes PDg1 and PDg2 using two G pixels, and red photodiodes PDr1 and PDr2 and blue photodiodes PDb1 and PDb2 using two Mg pixels, respectively. The sources of Tr1g, Tr2g, Tr1r, Tr2r, Tr1b, Tr2b are connected. In this case, there are six transfer transistors. Transfer wirings 111G1, 111G2, 111MgR1, 111MgR2, 111MgB1, and 111MgB2 are connected to the gates of the transfer transistors Tr1g, Tr2g, Tr1r, Tr2r, Tr1b, and Tr2b. The drains of the transfer transistors Tr1g, Tr2g, Tr1r, Tr2r, Tr1b, Tr2b are connected in common and connected to one reset transistor Tr _SEL , and so-called floating between the drain of the transfer transistor and the source of the reset transistor Tr _RES. The diffusion FD is connected to the gate of one amplification transistor Tr _AMP . The drain of the reset transistor Tr _{RES and} the drain of the amplification transistor Tr _AMP are connected to the power supply wiring 112 (Vcc). The gate of the reset transistor Tr _RES is connected to the reset wiring 113. Further, the source of the amplification transistor Tr _AMP is connected to the drain of one selection transistor Tr _SEL . The source of the selection transistor Tr _SEL is connected to the vertical signal line 115 and the selection wiring 114 is connected to the gate thereof.

In this way, by sharing the reset transistor Tr _RES , the amplification transistor Tr _AMP, and the selection transistor Tr _SEL with respect to a total of four pixels, that is, two Mg pixels and two G pixels, the above-described Mg pixel and G pixel are slanted. In addition to the effect of the shifted arrangement, the area of the MOS transistor of the pixel can be further reduced. Accordingly, since the photodiode area (opening area of the light receiving portion) can be further increased, the saturation charge amount and sensitivity can be further improved.

  22 and 23 show the case where four pixel transistors are provided as the pixel transistors, but the present invention can also be applied to the case where the pixel transistors shown in FIG. 26 have three MOS transistors. In that case, the reset transistor, the amplification transistor, and the like can be shared.

  As described above, according to the present embodiment, a 2 × 2 spectral structure (that is, a structure in which the G detection sensor and the B and R detection sensors are separated and B and R can be detected from the same pixel) is used. In addition, since the G detection sensor (pixel) and the B and R detection sensors (pixel) are alternately arranged in the horizontal and vertical directions, the calculation formula for obtaining the R, G, and B color signals of the virtual pixel is simplified. be able to. Even if the on-chip color filter of the first embodiment is not provided, color separation is possible, the cost can be reduced, and the sensitivity can be improved. Furthermore, the sensitivity can be further improved by sharing the floating diffusion.

  In the above example, a green (G) filter is used as a primary color filter and a magenta (Mg) filter is used as a complementary color filter. However, the present invention can be applied to other combinations of primary color filters and complementary color filters.

1 is a schematic configuration diagram showing a first embodiment of a semiconductor image sensor according to the present invention. It is sectional drawing which shows the semiconductor sectional structure of the 2nd pixel (G pixel) of 1st Embodiment of the semiconductor image sensor which concerns on this invention. It is sectional drawing which shows the semiconductor sectional structure of the 1st pixel (R / B pixel) of 1st Embodiment of the semiconductor image sensor which concerns on this invention. It is a schematic block diagram which shows 2nd Embodiment of the semiconductor image sensor which concerns on this invention. It is sectional drawing which shows the semiconductor sectional structure of the 2nd pixel (G pixel) of 2nd Embodiment of the semiconductor image sensor which concerns on this invention. It is sectional drawing which shows the semiconductor sectional structure of the 1st pixel (Mg pixel) of 2nd Embodiment of the semiconductor image sensor which concerns on this invention. It is explanatory drawing with which it uses for description of the computing equation which calculates the color signal of the semiconductor image sensor which concerns on this invention. It is the figure (the 1) which extracted the imaging area | region of 3rd Embodiment of the semiconductor image sensor which concerns on this invention. It is the figure (the 2) which extracted the imaging area | region of 3rd Embodiment of the semiconductor image sensor which concerns on this invention. It is the figure (the 1) which extracted the imaging area | region of 4th Embodiment of the semiconductor image sensor which concerns on this invention. It is the figure (the 2) which extracted the imaging area | region of 4th Embodiment of the semiconductor image sensor which concerns on this invention. It is a schematic block diagram which shows 5th Embodiment of the semiconductor image sensor which concerns on this invention. It is a schematic plan view of the principal part in the 2nd pixel of 5th Embodiment. It is sectional drawing on the AA line of FIG. It is a schematic plan view of the principal part in the 1st pixel of 5th Embodiment. It is sectional drawing on the BB line of FIG. It is a schematic block diagram which shows 6th Embodiment of the semiconductor image sensor which concerns on this invention. It is a schematic plan view of the principal part in the 2nd pixel of 6th Embodiment. It is sectional drawing on the AA line of FIG. It is a schematic plan view of the principal part in the 1st pixel of 6th Embodiment. It is sectional drawing on the BB line of FIG. It is an equivalent circuit diagram which shows other embodiment of the semiconductor image sensor which concerns on this invention. It is an equivalent circuit diagram which shows other embodiment of the semiconductor image sensor which concerns on this invention. It is a principle figure of a Bayer type color filter used for explanation of calculation of a color signal of a semiconductor image sensor which has a Bayer type color filter. It is a schematic block diagram of the conventional image sensor without a filter. It is a schematic equivalent circuit diagram of a CMOS image sensor.

Explanation of symbols

  31, 70, 80, 90 .. Semiconductor image sensor, 33 [33A, 33B], 33i, 73i .. Virtual pixels, 73 [73A, 73B], 83 [83A, 83B], 93 [93A, 93B],. ..Pixel, 35, 36..Peripheral circuit, 32..n-type semiconductor substrate, 42..p-type semiconductor well region, 43, 44, 56..n-type semiconductor region, PDb..blue photodiode, PDr. · Red photodiode, PDg · · Green photodiode, 57 · · p-type accumulation region, 75 · · Magenta (Mg) filter, 76 · · Green (G) filter, 47, 48, 58, FD1, FD2, FD3, Floating diffusion

Claims (12)

A semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading signal charges of the photoelectric conversion means,
The first pixels and the second pixels are alternately arranged in the horizontal direction and alternately in the vertical direction,
A complementary color filter is disposed in the first pixel, and a primary color filter is disposed in the second pixel;
The first pixel includes a plurality of photoelectric conversion regions having different depths,
The intersection area connecting the diagonally continuous first pixels and the diagonally continuous second pixels is a virtual pixel,
A semiconductor image sensor, wherein three primary color signals of the virtual pixel are generated from signal charges accumulated in at least two first pixels and two second pixels adjacent to each other in an oblique direction. A semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading signal charges of the photoelectric conversion means,
The first pixels and the second pixels are alternately arranged in the horizontal direction and alternately in the vertical direction,
The first pixel includes a plurality of photoelectric conversion regions having different depths,
The intersection area connecting the diagonally continuous first pixels and the diagonally continuous second pixels is a virtual pixel,
A semiconductor image sensor, wherein three primary color signals of the virtual pixel are generated from signal charges accumulated in at least two first pixels and two second pixels adjacent to each other in an oblique direction. A semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading signal charges of the photoelectric conversion means,
The first pixels and the second pixels are alternately arranged in the horizontal direction and alternately in the vertical direction,
A complementary color filter is disposed in the first pixel, and a primary color filter is disposed in the second pixel;
The first pixel includes a plurality of photoelectric conversion regions having different depths,
A complementary image signal of the position of the second pixel is generated from the first pixel above and / or below and / or right and left of the second pixel. A semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading signal charges of the photoelectric conversion means,
The first pixels and the second pixels are alternately arranged in the horizontal direction and alternately in the vertical direction,
A complementary color filter is disposed in the first pixel, and a primary color filter is disposed in the second pixel;
The first pixel includes a plurality of photoelectric conversion regions having different depths,
A primary image signal of the position of the first pixel is generated from the second pixel above and / or below the first pixel. A semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading signal charges of the photoelectric conversion means,
The first pixels and the second pixels are alternately arranged in the horizontal direction and alternately in the vertical direction,
The first pixel includes a plurality of photoelectric conversion regions having different depths,
A virtual multiple color signal at the position of the second pixel is generated from the first pixel above and / or below the second pixel. A semiconductor image sensor comprising a plurality of pixels including a photoelectric conversion means and a MOS transistor for selectively reading signal charges of the photoelectric conversion means,
The first pixels and the second pixels are alternately arranged in the horizontal direction and alternately in the vertical direction,
The first pixel includes a plurality of photoelectric conversion regions having different depths,
A primary image signal of the position of the first pixel is generated from the second pixel above and / or below the first pixel. Adjacent first pixels that are diagonally adjacent share a floating diffusion,
2. The semiconductor image sensor according to claim 1, wherein two adjacent second pixels that are obliquely continuous are taken as a set, and the set of second pixels share a floating diffusion. Adjacent first pixels that are diagonally adjacent share a floating diffusion,
3. The semiconductor image sensor according to claim 2, wherein two adjacent second pixels that are obliquely continuous are taken as a set, and the set of second pixels share a floating diffusion. 4. Adjacent first pixels that are diagonally adjacent share a floating diffusion,
4. The semiconductor image sensor according to claim 3, wherein two adjacent second pixels that are obliquely continuous are taken as a set, and the set of second pixels share a floating diffusion. 5. Adjacent first pixels that are diagonally adjacent share a floating diffusion,
5. The semiconductor image sensor according to claim 4, wherein two adjacent second pixels that are obliquely continuous are taken as a set, and the set of second pixels share a floating diffusion. Adjacent first pixels that are diagonally adjacent share a floating diffusion,
The semiconductor image sensor according to claim 5, wherein two adjacent second pixels that are obliquely adjacent to each other are taken as a set, and the set of second pixels share a floating diffusion. Adjacent first pixels that are diagonally adjacent share a floating diffusion,
7. The semiconductor image sensor according to claim 6, wherein two second pixels adjacent to each other in an oblique direction are set as one set, and the two second pixels in each set share a floating diffusion.

Images